1. Field of the Invention
The present invention relates to a vibrating mirror element and an optical scanner, and more particularly, it relates to a vibrating mirror element including a driving portion having a free end connected to a shaft portion and an optical scanner including the vibrating mirror element.
2. Description of the Background Art
A vibrating mirror element including a driving portion having a free end connected to a shaft portion is known in general, as disclosed in Japanese Patent Laying-Open No. 2009-192967, for example.
The aforementioned Japanese Patent Laying-Open No. 2009-192967 discloses an optical reflecting element (vibrating mirror element) including a mirror portion swingable on an axis extending in a first direction (direction X), an inner frame body connected to the mirror portion and swingable on the axis along with the mirror portion, a shaft portion connected to the inner frame body, a meandering vibrator (driving portion) including a free end and a fixed end, and an outer frame body. In the optical reflecting element disclosed in the aforementioned Japanese Patent Laying-Open No. 2009-192967, the meandering vibrator includes a plurality of piezoelectric actuators extending in a second direction (direction Y) orthogonal to the first direction, and is formed to swing the mirror portion by deforming the piezoelectric actuators. The free end of the meandering vibrator is connected with the inner frame body through the shaft portion on a side closer to the mirror portion in the direction X and on one side in the direction Y. The fixed end of the meandering vibrator is fixed to the outer frame body on a side opposite to the mirror portion in the direction X and at a substantially central portion in the direction Y.
In the optical reflecting element disclosed in the aforementioned Japanese Patent Laying-Open No. 2009-192967, however, the fixed end of the meandering vibrator is fixed to the outer frame body on the side opposite to the mirror portion in the direction X, and hence the fixed end is so separated from the mirror portion in the direction X (extensional direction of the axis) that the size of the optical reflecting element is disadvantageously easily increased in the direction X (extensional direction of the axis). Further, the free end of the meandering vibrator is connected with the shaft portion on one side in the direction Y (direction orthogonal to the axis) while the fixed end of the meandering vibrator is fixed to the support portion at the substantially central portion in the direction Y (direction orthogonal to the axis), and hence the free end and the fixed end are separated from each other in the direction Y (direction orthogonal to the axis). If the plurality of piezoelectric actuators are concavely or convexly deformed in the vertical direction (direction orthogonal to the directions X and Y) when the meandering vibrator does not drive the mirror portion, therefore, the free end disadvantageously inclines with respect to the fixed end due to the separation between the free end and the fixed end in the direction Y. Therefore, the mirror portion connected to the free end also disadvantageously inclines with respect to the fixed end when the meandering vibrator does not drive the mirror portion.